Why people think incest is wrong

I am an incestuous person, I am 23m and my older sister is 28f and we have been in an incestuous relationship for about 3 years. I have been to many therapists, counselors etc, they all tell me incest is wrong and to stay away from my sister, I am so confused why this is, I can’t understand why it is wrong, it is only considered incest if it is between two people who are parent and child, siblings cannot have kids that are genetically defective, I know that there are many incestuous people in relationships with their siblings. I do not understand why I am considered a sicko when I am in a happy relationship, if I am so sick why are there so many rights for everyone else and not for us? I don’t understand why I am considered sick and not allowed to be in a relationship like I want, isn’t love love? I don’t understand what the problem with incest is, they say it is because of birth defects, I am male and my sister is female, I would never have kids with her. I don’t understand why I am not allowed to love whoever I want?